A) Field of the Invention
This invention relates to a method for producing a p-type ZnO based compound semiconductor layer and a method for producing a ZnO based compound semiconductor element. This invention also relates to a p-type ZnO based compound semiconductor single crystal layer, a ZnO based compound semiconductor element, and an n-type ZnO based compound semiconductor laminate structure.
B) Description of the Related Art
Zinc oxide (ZnO) is a direct transition-type semiconductor which has a band gap energy at room temperature of 3.37 eV, with a relatively high exciton binding energy of 60 meV. Use of zinc oxide has the advantage of reduced raw material cost as well as smaller influence on environment and human body. Accordingly, there is a high demand for a light-emitting device using ZnO having a high efficiency and low power consumption with reduced burden on environment.
However, the ZnO based compound semiconductor suffers from difficulty in realizing p-type electroconductivity due to self-compensation effect caused by the strong ionic property. For example, investigations have been conducted to develop a p-type ZnO based compound semiconductor having practical properties by using, for example, a Group 15 element such as N, P, As, or Sb, a Group 1 element such as Li, Na, or K, and a Group 11 element such as Cu, Ag, or Au as an acceptor impurity (see, for example, Japanese Patent Application Laid Open Nos. 2001-48698, 2001-68707, 2004-221132, and 2009-256142, and Japanese Patent No. 4365530).